I know I cant be t the only one that's thought of this. With the links being widely available, why don't such rifles exist? A belt is not a magazine, so it gets around the hi cap laws. Only thing I can think of are reliability and cost issues. Any thoughts on this?

you better read the law again.

LOL wut? I think you best read the law again because your wrong. The law, relevant portion below, specifically INCLUDES belts.

Sec. 53-202w. Large capacity magazines. Definitions. Sale, transfer or possession prohibited. Exceptions. (a) As used in this section and section 53-202x:
(1) “Large capacity magazine” means any firearm magazine, belt, drum, feed strip or similar device that has the capacity of, or can be readily restored or converted to accept, more than ten rounds of ammunition, but does not include: (A) A feeding device that has been permanently altered so that it cannot accommodate more than ten rounds of ammunition, (B) a .22 caliber tube ammunition feeding device, (C) a tubular magazine that is contained in a lever-action firearm, or (D) a magazine that is permanently inoperable;

As to your question about belt fed rifles, they do exist. Here are just a few links:
http://www.atlanticfirearms.com/component/virtuemart/shipping-oversize-rifles/rpd-rifle-bi-pod-drum-detail.html?Itemid=0
http://www.aresdefense.com/?page_id=126
http://www.gunbroker.com/All/BI.aspx?Keywords=belt+fed

Edit to add: Depending on one's interpretation of the law, it would appear, because of the way the state now defines "detachable magazine"  with respect to so called "assault weapons", semiautomatic centerfire belt fed rifles would have to conform to the single feature ban which means if they have a; folding/collapsible stock, pistol grip, forward pistol grip, or grenade/flare launcher it would be considered by the state to be a so called "assault weapon". If so, unless it was manufactured prior to 9/13/94, cannot be transferred/sold to anyone within CT unless that person is a member of the exempted class.

I agree, cost issues SUCK!

Pure gun porn. Highly arousing as well.

I'm stiff....

Pure awesomeness.