> My TV only has HDMI inputs making it much more tricky to play my retro consoles.
> Time to invest in some better connections now I guess.
Not sure if this helps, but I was surprised to find out that my Denon HDMI A/V Receiver takes component inputs (like the HD Wii cables for example), upconverts it, then send it out through HDMI
It also has composite (R/W/Y) and S-video for other systems. I haven't tried those inputs, but I would imagine it upconverts those signals too (since they are all analog, just like component).
Maybe all you need is an upconverting receiver? You can probably find one used on Craigslist.
I actually scored mine (which was $900 when new!) from a yard sale for $2. The guy thought the rear channels didn't work, but they work just fine. I think he didn't know how to work the surround sound settings.