1) Does Sirius have a portable, Walkman like unit (not just one
you
can move from the car to the home).

No--perhaps they will before Stern actually gets there at year end.
More likely, it will be into 2006 a bit.

2) How good is the reception inside an office building?

Sirius has some significant problems with receptions inside a
structure. XM is really much better in such an environment, but if you
don't have a clear view to the sky from within a metal structure it is
a longshot. The best thing to do is to buy one and try it. If you
can't get the preview channel, you won't get the service after
activation.

3) What's a good brand or a good place to search for reviews?

If I were buying a Sirius radio right now (but I wouldn't be) I would
be looking at the Sportster, I think.

Now might be a good time to get her to consider Opie & Anthony; they're
already at XM and they can tell fart jokes at least as well as Stern
can.