I found one more for you 3 3/4" round with 2 mounting studs but they're $17.00 a pair off eBay with free shipping - still not exactly what you're looking for but the more options you have the better - I know - still 1/4" larger than your opening but I thought I would throw it out there for you to check out anyway.
http://www.ebay.com/itm/Round-Red-Li...xSXb5u&vxp=mtr