Newegg.com - BIOSTAR TForce TP35D2-A7 LGA 775 Intel P35 ATX Intel Motherboard - Intel Motherboards

I don't know how much room you absolutely need, but you got some space in there.

here's a Micro mobo:

Newegg.com - GIGABYTE GA-MA69GM-S2H AM2 AMD 690G HDMI Micro ATX AMD Motherboard - AMD Motherboards

the PCI x4 is on the other side of your x16 slot, so I think you'd be fine using this one, just not a very roomy motherboard :/

Newegg.com - ASUS M2N32-SLI Deluxe Wireless Edition AM2 NVIDIA nForce 590 SLI MCP ATX AMD Motherboard - AMD Motherboards

I like that one, you can install your video card in your second PCIE x16 slot, and put your tv tuner card in that x4 slot with no problem I think

So there's a few options for you to look at, hope I'm a little bit of help