"29 inch" tires are the same diameter as 700c, so any moderately wide 700c tire (say maybe 32 mm and up) would work as well, giving you more options. The Schwalbe Big Apples chaadster mentioned have a good reputation. The Panaracer T-Serv is another tire that may be worth considering. The eBay seller Wheel & Sprocket is selling them in 700c x 35 for $28.50 with free shipping.