DHCP & IP ranges (10.0.2.0/22?)

[RalfGesellensetter <rgx@gmx.de>]

Dear list,

I'd like to ask two (connected) questions:

the current configuration allows over 500 clients (given 10.0.2.0/23),
however I wonder if it was a big deal to just double that range by 
making it 10.0.2.0/22?

Furthermore, we have a lab that happens to use up twice the amount of IP 
addresse, because (now!):

 * every computer has got _two_ network cards
 * additional to onboard nic (not supported by earlier kernels) there 
   is a pci nic (3com) in every computer.
 * students (and probably also teachers) cannot be kept from
   un/re-plugging cables, so you never know what nic is connected.
 * each computer, hence, got 2 mac addresses (used exclusively!)

Now, I wonder if it is possible to assign each IP twice in dhcpd.conf
(once for each network card, because those are used exclusively).

Thank for any clarification.
Regards
Ralf