It is about more than just having the correct number of wires. You have to look at the impedance of the lines. One company was able to do a demo with 100baseT over barbed wire seperated by several inches of air, but only because that width of free space matches the impedance of cat5 UTP.
Unfortunatly Cat5 is 100ohm and RG6 is 75ohm. Every incidance of impedance mismatch causes a reflection. Going from 100ohm to 75ohm gives a negative reflection, and the reverse causes a positive one. Realy short mismatches (like a conector) largely cancel out but long cable runs...
The short answer is that for a reliable high bandwidth solution you are probably better off ignoring the coax. 802.11n should give you all the wireless bandwidth you need, g tends to have a real throughput of around 20Mb but n claims 100Mb (DVD rate about 5Mbps, broadcast DTV up to 19.4Mbps, BlueRay up to 40Mbps). Or you could future proof yourself and run Cat5e, works with Gigabit ethernet.
And yes, IAAEE (I Am An Electrical Engineer)