bridging for wifi roaming

[Jolan Luff <jolan@lithely.net>]

I'm not sure where to start here, so I thought I'd ask for help.  My
network layout looks like this:

inet (dhcp)/fxp0 -- [pfbox] -- wifi lan (192.168.1.1)/wi0
                       |
         local lan (192.168.0.1)/fxp1
                       |
         local lan (192.168.0.2)/fxp0
                       |
                 [workstation] -- wifi card (unconfigged)/wi0

Currently, laptops have static ips on the 192.168.1.0/24 subnet and
connect to the pfbox's hostap card.  The two machines are connected via
an 8 port switch.  The pfbox is 150' away from the switch, with
the workstation machine right next to it.  What I'd like to do is roam
between the two hostap cards as seamlessly as possible, hopping onto the
one with the best signal.  To my untrained eye, it looks like this might
be able to be accomplished with bridging & vlans.  Unfortunately, I
haven't had an opportunity to get familiar with either.  I would like
to be able to do the following:

1) Keep the same IP when hopping.
2) Be able to access the other machines on my network.
3) Not have current connections die.  (Doubt this...)

Is this possible with bridging/vlans or is this something that needs to
be addressed with mobile ip (or some other network technology)?  The two
wi0 cards are PRISM2.5 dlink 520's so they do bridging.

- jolan