I'm kind of hesitant to update my VITA-1000 (OLED) to keep playing online, so what I'm going to do is to wait and see what comes of that HENkaku reverse-engineering project and the kernel exploit. It should be possible to spoof the firmware version on the VITA itself.
Do we know why hacks/kludges like vita_update_blocker work for a short time before being disabled? Would it work if, instead of a "proxy server" we can emulate a "default gateway"? What I mean is, suppose your home WiFi GW is 192.168.1.1 and one of your windows machines is 192.168.1.2, on that machine you run the VITA_GW_Emu and on your VITA you enter 192.168.1.2 as your GW. That way the VITA cannot bypass the proxy settings and use 192.168.1.1 anyway for certain sneaky lookups. So it would basically be a combination of the functionality of a packet sniffer and the proxy (injecting spoofed information where needed).
You can play around a bit and change the default GW and use Google's DNS (8.8.8.8/8.8.8.4) but that will fail.