I had some regular e-mail contact with LocoSys since I bought my 5Hz LS20031 GPS board from Sparkfun
LocoSys informed me that in June or July, they are going to propose an upgrade applicable to the LS20031. The GPS will then be able to have a 10Hz update rate.
I'll post more information when available. in the meantime, here's the latest LocoSys product table for those interested: 2009DM.pdf