Hey Dennis, I'm still planning to do Twents Open as you know. The plan is to do most main events on the first day and do fun stuff (still secret) and side events on the 2nd day. If it's up to the organisor to set the time limit at that competition I don't see a problem with making a 4 hour limit or such. Provided you would not be the only one to try a bit amount of course, I hope Tim will come too.
What I saw from some posts (I didn't read all, no time) was that there was a bit confusion about what the purpose of multiBLD exactly is. Maybe we should have such things in the WCA regulations too in the future? Just a side note but multiple blindfolded sounds to me as: 'do as many cubes BLD in a row as you can', which obviously doesn't say anything about time, but of course there is the practical issue that competitions have certain time limits. I think it'd be very bad to put in a 'hard' limit of for example 2:30 in the standard regulations, it'd be good if the organisor can decide about that (I'd call that a 'soft' time limit).
If that's going to be the case (or it is already in fact) maybe there should be guide lines like: 'prefered time limit' somewhere? It'd be weird if one competion would have a 1 hour time limit and the other 6.
anyway, I suck at multiBLD anyway since I don't have a memo system, I wish all you guys who plan to do crazy number the best of luck!