I've laced 28" wheel sets with timetec rims and carbonal rims both are good quality for the price IMHO.
240g for a 29er with 30mm outer is pretty light, drop them an e-mail if you don't find it at the web shop, they should be able to do it.
I've asked for rims with 160kg max load for a tandem and they at least can ad carbon fiber to bee frims up.