If you dont mind 16-bit then an LCDTV is almost the same price as most Amiga dedicated scandoublers. They can also operate as a MON switcher if you get one with a VGA input (for your Voodoo) and RGB SCART for the native.
If you have a video slot on your Amiga, the best scandoublers are the ARXON and the Petsoff. They are both 24-bit and fully AGA compatible. Although they are both reasonably rare they come up from time to time on ebay.
The best value scandoubler is the one built into the Picasso IV @£150-£180 and including an RTG gfx card they are great.
