no. the dreamcast has only 16mb of ram. there is no way a 26mb rom will work even if an emulator is written. go play project 64 on your PC or buy an n64 since you say you have a real cart.
and for reference, if you are ever told 'no, this doesnt exist' and you decide to give your own idea for how to do it, think this: "can i make it on my own?" If the answer is no, then whatever you have said has either been discussed before, or has not been because it wouldn't work. The Dreamcast emulation scene has existed for 5 years, and it has pretty much been decided that N64 emulation discussion is a moot discussion. If you want to read some lengthy discussions about why it can or can't be done, I would suggest going to
www.dcemulation.com and searching their forums for "n64 dreamcast" or something like that and read what has been said about it.