I've had quite a few ideas about this, and have come up with several different tricks.
(H1 = Hand one, H2 = Hand two, H1/H2 involved both hands, H1-H2 pen switches hands)

Sonic Ladder
H1 Sonic 12-23 -> H1 Sonic 23-34 -> H1-H2 Sonic 34-12 -> H2 Sonic 34-23 -> H2 Sonic 23-12

Sonic Ladder Extended (44 denotes combination of both hands' pinkies, quite difficult)
H1 Sonic 12-23 -> H1 Sonic 23-34 -> H1-H2 Sonic 34-44 -> H1/H2 Sonic 44-34 -> H2 Sonic 34-23 -> H2 Sonic 23-12

Cardiod Switch
H1 Thumbaround -> H1-H2 Wiper Reverse T12-T12 -> H2 Thumbaround -> H2-H1 Wiper Reverse T12-T12

The notation is quite messy, and I'm still working on several other tricks/names. I've gotten all of these to work so far, I'm far from doing them consistently, though.

But I recommend others work on this (those who have time to learn new tricks/know them all...) because it is taking a whole new direction. It may look sloppy, but I can see how they can be come second nature, as with most tricks.

Feedback, questions, comments, new tricks, etc (Encouragin' veterans to try these out/figure shit out...)

I would recommend that you don't try to name your combos.

If you could provide a video, that would be helpful, cause I'm not sure exactly how these two-handed tricks would work. For example, on a two-handed sonic, is it R3R2 - R2L1, or R3L2 - L2L1, or do you do a full sonic with your right hand and grab it with your left and continue the charge motion?

This belongs in the research dept!
The notation is great.

Erm, with the extended ladder, you sonic from 34, to in between your two pinkies. The pinkies now act as a seperate slot (yes, I HAVE gotten this to work... once, it will be easier for those who are more adept with shadows/charge from pinkies). With the normal ladder, yes, it is partial charge, switch, continue charge motion. I'm sure there are TONS of new tricks with the "extra slot", the key is learning to master, which, unfortunately, I'm too unskilled to do and I'm pretty sure a lot of people will lose motivation quickly.

@UED: I don't have access to the Research Department.

First up, don't name the damned combos. Second join the RD (PM zombo about it). There is already ongoing work about notation for two handed combos and this would also make a good project.

As for the notation, the first two make no sense to me. I think you mean Sonic reverse for all of them, no? Its not even possible for a sonic to go from 12 to 23... Also in the first one, you go from H1-H2 by going 34-12. I can see how this would work, kinda... but then you go 34-23 on H2. That makes no sense, how the hell did the pen suddenly jump from 12 to 34? Wtf? So basically, unless you can show me a video of at least how the pen should move (even if you can't do it) then I have no idea what you are talking about.

Concept isn't bad though, all in all.

i think if u make a video will be better

You're right, I had it all fucked up.

Here it is with changes:

Sonic Ladder
H1 Sonic Reverse 12-23 -> H1 Sonic Reverse 23-34 -> H1-H2 Sonic 34-34 -> H2 Sonic 34-23 -> H2 Sonic 23-12

Same changes for the second...

So... Research Department, eh?

Those are variations and extensions of the Sonic Transfer:
http://www.pentrix.com/pentix/videos/twohanded/index.html

As for the Cardioid Switch, I know someone once made a thread about an alternating TA 2h combo, but the transfer involved dropping the pen onto the opposite hand (placed below) instead of wipers. The thread was either at Pentix or UPSB; I can't remember which.

Edit the main post dude, it's the most confusing thing I've ever read

@Shoeman: Stole the words outta my mouth...

@Retro: Stole the idea right outta my head... Idea theif... lol jk, but yeah I always thought about doing Sonic R34-23 > Sonic R23-12 > Sonic R12-R1L1 > Sonic (Normal/Rev) R1L1-L12 > Sonic Rev 12-23 > Sonic Rev 23-34... Basically a Sonic Rise from one hand's slot 34 to the other's. Good job of actually making a topic about it, I can just invision PS in a year or two when this concept is mainstream. Pen going from hand to hand constantly in a combo, would almost be annoying and too hard to watch.

Picture this mini combo:
*Begin with pen in R34, then bring RH Towards left*
Sonic R34-L2R3 > Charge R3-L2 > Pass Rev R3L2-L23
While passing slide RH over LH until R4 is over top L3 While tilting hands 90 Degrees (Palm Down>Palm Left) > Right Pinky/Leftt Ring Around with L2 Push L23-L23 > Right Pinky Around R23-__*While sliding Left hand away from right hand to enable pen to travel only around R4. When pen goes around R4 there will be no recieving slot. So once pen is almost around 4 Horizontaly Rotate RH (Palm Left>Palm Right) and catch in 34 making the R4 Around 1.5 spins*... Holy fuck. Is that even possible? I don't doubt PS will be at that level in a few years at the rate its growing dudes.

the RD is working on other ways to name two hands. maybe we'll agree on something and publish a paper.