I don't know if we'll ever see rerecording in MAME, really. Reasons being:
1. Savestates are extremely screwy in this emulator, currently. Sometimes they do what they're supposed to, other times (as with Gradius, to name one example of many) they mess up the graphics and/or freeze the game when you load one.
2. Fixing this is not exactly a high priority of the MAME team, to put it mildly.
Extremely sad, I know, but that seems to be the truth.
but then you take my 75 perchance chance of winning, if we was to go one-on-one, and then add 66 and two-thirds ch...percents...i got a 141 and two-thirds chance of winning at sacrifice