sensitive DGPS enabled GPS modules

Hi - I’d be really interested in seeing SFE carry some DGPS enabled GPS modules that can be used indoors. These seem to be fairly rare, but it does look like the U-Blox LEA-4H (http://www.u-blox.com/products/lea_4h.html) would fit the bill quite nicely.

Anybody know of any others? (besides those made by U-Blox)

My goal is to pair up two of them and use one to generate DPGS corrections for the other. It would also be possible to get the raw pseudorange information from two SIRF III receivers and use one to correct the other, and then write my own code to compute the fixed position - but using a DGPS enabled receiver would just make it so much easier…

Did you see the new gps receiver at the frontpage?