Do monks HAVE to accept anything offered to them? Does a theravada abbott have to accept everything / anything that is offered to them? I'm referencing technology, things beyond requisites. 

I know it is important for abbotts to set a good example and to create trust through their actions.
I can't speak to the Pratimoksha followed by Theraadans, however, according the the Pratimoksha of Mulasarvastivada (which I foillwed when I was a monk), there are certain items no monk can possess (e.g. a meditation mat made of black sheep's wool) - so if offered, one might accept it - but then turn it over to the abbot. Otherwise, the only other relevant vows concerned accepting what was offered in terms of food. I imagine these restrictions would be similar for Theravadans. As for technology, in my monastery, we had lots of teachings that had been digitized, for walkmen, MP3 players and computers were ubiquitous.
Hope this helps.