I would be interested too! However, being in Canada, maybe there would need to be 2 round robins - a US one and a Canada one (ease of postage & length of time).
I've participated in a few of these and one thing I would recommend doing is getting everyone to agree to a set # of days you get to keep the package for. The last one I participated in took 6 months to finish up and even then it never did finish - someone just kept the whole darn thing instead of sending it on. We did have a limit of 2 days per person (if you know it's coming you really can be prepared with the stuff you want to send on it's way ahead of time) but obviously someone decided that was too short!
Another suggestion would be to make a "rule" that not only do you take one, put one in as far as swapping out stuff goes but quality must equal as well. When I got the RR in one I participated in, someone took out all the good quality items and put in crap! I was embarrassed to send it on to the next person so I went out and purchased things of quality to include in it because I felt bad about what they were going to be getting. You don't take a whole sheet of Making Memories large letter stickers out and put in a half sheet, incomplete, of Sandylion mini letters (that was done!). Ya know what I mean?
Anyway, all that to say I would be interested in something like this if it happens! I'll even start the Canadian one if anyone up here is interested!
Keep me posted!
Jocelyn