PJ
do you have the room to take out your pizza on the peel? (pretend your oven opening is 4 feet from the back wall/corner and use a broom handle)
a generous 4x4 does not sound like much space to work inside??
I think a lot of ovens are built after the house (and many other projects) are done so they get put outside. Easier, safer, no smoking, less hassels I think.
Good luck either way!
XJ