Hey bud,
I started a MAME Archives collection back in v0.143ish and I have been silently updating it every release, the MEGA link is here...
https://mega.nz/#F!Kl9AxTAA!3n4trnsyXA4EVNScL-I-2w
... and it only contains everything from v0.201 upwards (note: I will delete some older stuff to make room for new releases in the coming months), but checking out the DATs/ARMAX section of each upload will get you all the Rollback DATs releases since v0.201, you just need to dig through folders to get them. (its designed to copy the entire thing into your existing collection folder)
If you need something earlier that is not listed there, I have every Rollback DAT since EgoElf and robber804 started the project back in the day and since passing it on to ARMAX at v0.132 I have all of his stuff as well, so if you are looking for something very specific let me know.
Thanks,
Mords