Slide mounted base for a Gold Cup.

Does anyone make one???  That would have a groove on the inside to fit over the Colt's rib. Also advice on what would be a good entry level red dot. We're thinking a 30mm Ultra Dot. Going with what we see a lot of here on the forum, and determined to stick with this one armed shooting in the coming year.... and will need to do it with a red dot sight. Just can't see the irons as well as I'd like shooting indoors. 
     This whole thing started innocently enough I guess.....shooting with a few of the local cops on Sunday mornings. Shooting close and fast with two hands at small ring of their silhouette targets. Actually, I got pretty good at it with my revolvers.  Then we started shooting one handed just for fun. You all know the rest. Not quite in over my head yet,...just pretty sure that a good dot sight will get more of the holes closer to the center.
                                                                                                          Thanks in advance;
                                                                                                                                        Bill

http://www.marvelcustomguns.com/1911_new_gold_cup.htm

WOW!! That was quick, and what we were looking for.
                                                                       Thank you Sir;
                                                                                              Bill

Just a note; If you send me the slide, bushing and barrel I will make one for $50 from 7075 Aluminum (Very strong Aluminum) that is completed on the slide so that it is inline with the bore of the barrel. If you send the scope and rings I'll cut the groves for the ring screws exactly where you want the scope mounted.

Appreciate your offer Sir. For now, we'll go with the marvel rib, and my buddy the gunsmith can mount it for us. And if we go back to shooting the open sights, the holes in the slide won't look all that bad with filler screws in them.
                                                                         Thanks again;
                                                                                               Bill