If you mean the Maemo SDK then no, you won't need that at all. Just do what you want directly in Ubuntu. I'm sure Ubuntu has fakeroot and dpkg-deb, just as regular Debian. As you're only unpacking/packing, moving files, possibly editing ascii files there's nothing that needs the Maemo SDK there. It's simple.

Edit:
About fakeroot: Fakeroot is so that you can be logged in as yourself, and not root, and still be able to create an archive file (in this case the .deb) where the files in the archive are owned by root.root and not the user you're logged in as.

E.g.
dpkg-deb -b <blablabla>
would create a .deb with files owned by you.yourself (as can be checked with dpkg-deb -c filename.deb), just prepending the command with the 'fakeroot' command will fix it so that the files in the .deb archive are owned by root.root:
fakeroot dpkg-deb -b <blablabla>
This makes working with .e.g. .deb files simple and any non-privileged user can do it.