My suggested to-do for N900 GPS on Leste based on my own reverse engineering of the GPS system on the N900:
1.Update current N900 GPS bits for Leste to use the actual structures and constants from Nokia rather than hardcoding everything and trying to work from blind reverse engineering and potentially not catching all the corner cases and other things that may not show up in regular testing. This means dealing with LS_HYBRID_TRACKING_REQ, LS_HYBRID_TRACKING_NTF and PNS_SUBSCRIBED_RESOURCES_IND.
2.Handle LS_HYBRID_TRACKING_RESP and LS_GPS_STATUS_IND (although it would appear that location-daemon doesn't actually do anything with LS_GPS_STATUS_IND other than some debug logging)
3.Handle the case where the cellular modem changes state (i.e. correctly initializing GPS when the modem comes back up or whatever which would include airplane mode I suspect)
4.Reverse engineer location-proxy and liblas (and libisi if need be) and come up with a suitable clone for Leste that does what is needed and make that blob load as required.
and 5.Related to that, look into the wappushd stuff and whether location-proxy actually does anything with that and whether Leste needs to do anything with that (I cant tell just by looking at the binary if it does or not)