I've been to Taiwan /Taipei several times as business trip.
Most of time, agent find me out and ask for WG once they find me out as Japanese.
Normally, there are several patterns:
Agent call girls and you can see / choose them at cafe or other place
WG comes to your hotel room and you can decide if you like or not
Agent arrange cheap hotel near by and WG comes to the hotel room.
I normally ask WG to come over my room and never refused.
I have several name card of agent, they operate business as Tea shop or other bar, karaoke etc..
Price range from 3500-5000 NTD for one play (depend on lady.. some are so rush and some are not..)
average is around 4000NTD when I visited last time. (Actually 2 weeks ago)
This is much cheaper than going out for drink (around 1000-2000) and ask girls to go out (4000-xxxx)
but only few agent has pics, so its kinda lucky draw. (even you have chance to ask for changes)
I was also try to find any website but not really able to find. Only site I could found was
http://8big.idv.tw/index1_3.htm
Those are basically for massage at private place or they come to hotel. (I guess only HJ..not sure..)
I didn't have chance to try, but since I love massage as well, this might be an option.