Hmm... looking at that I now think it is NOT a Rocky Mountain! Seat stays, junction of chainstays, angle of BB support tube are all different, no head gusset, brake cable bosses look different too.
Know it's of no real help, but I have the same frame knocking around, only without the e-stays.
Same tube set, head tube gusset, drop outs, 1 1/4" headset, same diameter seat tube, identical drop outs and cable thingies, just standard chainstays.
Was given to me by the bike shop I used to race junior for many moons ago, had their own stickers on but stripped them off years ago, pretty sure it dates from '90 / '91.
Would still be interested to know who made them tho.