One of the problems is that it needs to do more than just be a point defense fighter, day-light and not-so-bad weather nowadays. The cost and weight will increase so much as you make it multi-role, it will be in the F-16 class before you know it. On the other hand, if you can afford to leave out some of the requirements of the multi-role aspect, under todays budgets, you have no other option than to combine it with your trainer fleet. So then you'll have a Yak-130, AT-50, M346, Hawk, etc.
Anyway, we have those, and the LCA, FC-1/JF-17, L-159. The Gripen is pretty light as well.
Indeed not much in the western market for above reasons. With no domestic need for it, and other industries booming in this area, I wouldn't be surprised if no US light fighter/combat aircraft will ever see the light of day. I guess it needs times like the Cold War for the US to offer light-weight non-complicated fighters again... and less F-16s on the second hand market.
@ Viggen, never been a fighter? The Hawk had actually a secondary air defense task during the Cold War, armed with AIM-9 Sidewinders and cannons. I think even in Finland (that's why they had so many, weren't allowed to have more 'real' fighters) and maybe Switzerland.