Inexpensive Image Inversion/Mirroring?

This is a bit off the normal topic for here, but I figured if someone somewhere knew how to get this done, it would be here.

I'm looking for a method to invert/mirror an image (horizontally) that's coming from a computer and will finally end up on an LCD. The LCD is viewed via a single mirror.

I've found a few scan converters/scalers that can handle it, but there $350+ and I have to believe there's something cheaper I could use to accomplish it.

The restrictions I have are as follows:

• Can't switch to a CRT and do a yoke flip to accomplish the mirroring.
• The LCD monitor doesn't natively support mirroring the output, as far as I can determine.
• Adding a second mirror isn't an option because of space considerations.

In case you want to know why I need to do this - it's for a MAME Arcade Cabinet that has a mirror that the player sees which reflects the actual monitor.

Thanks in advance for any help...being able to do this would solve a ton of software limitations I'm currently running into since I could use anything and not just software that had a mirror/flip output option.

If you could let me know the lag, that would be great. If it was any other use, I'd have tolerance for lag but because it's an arcade cabinet any serious lag eliminates something as a possible solution - it would just make the situation worse (i.e., games would be unplayable).

I did take a look at that - I'm in utter shock at how much you've spent on processors just to test, to be honest .

Unfortunately, it looks like it's $800 - prob. more than I've spent on the entirety of the rest of the arcade cabinet! I'll keep an eye out on ebay for another one or the black box one to pop up. Fingers crossed! (Esp. since I missed one for what looks like $35 just last week)

And thanks!