internet+htpc<-wired->wndr3700<-5Ghz->wndr3700<-2.4Ghz->workstation
so the second wndr3700 would act as a bridge on 5Ghz but having the 2.4Ghz wlan activated there shouldn't be any loss (so i thought) as two completely different bands are used and the wndr3700 has some what 8 antennas build in as far as i know so it should be able to receive and transmit on both bands simultaneously
but from what i read here this setup will not work (pleas correct me)
Your proposed setup should work, assuming that using the 5 GHz band will give you enough throughput due to its reduced range vs. 2.4 GHz.
Why do you need to run wireless to the workstation? I'd connect via Ethernet if at all possible.