Network Design Advice

[Dean Kao]

We're redesigning our network and an interesting issue
came up.  Currently, our wan links in our network are unnumbered  
and we want to number them.  In our design plans, we want to
designate 10.128/9 to the wan network and subnet that further
into /21, which allows for 4096 networks.  If we number
the wan links, it'll only give us 2048 networks (assuming you use
a /21 for the wan link).  Is there any design tricks that I can use 
so I dont have to use up a whole /21 for just the two ips between 
the routers?  Or am I stuck losing all those ips.

Thanks!
Dean