I found a site on the world wide interweb that provides a comprehensive guide to running Ultima 8 in XP without DOSBox or any other programs of the like. I've tried it, and it seems to work OK, if a little slow, but I think I might have a few bugs to iron out there still. If I get it working smoothly I'll make a post about it. The site is -
http://members.iinet.net.au/~rsd/six.html
NOTE: My PC is quite old, the steps laid out in this guide will probably work a lot better for newer more powerful computers.