Camelbak offers a lot of attachments that use their Hydrolink attachment system. IIRC, Hydrolink accessories are compatible with Source bladders/accessories, and vice versa. The gas mask adaptors, and dirt covers from CB may interest some, and the
very handy Universal Tube Adaptor from Source is highly recommended. Of course, the Hydrolink feature makes replacing a defective hose much easier, and a spare hose is always a good idea. This kit (on sale) provides both:
http://source-military.com/product.php?id_product=34.
One thing I suggest is installing neoprene tube insulators, and camo covers over the tube+neoprene insulator.
I get mine here:
www.hydrationtubecovers.com. You'll need to cut/shorten the tube about 1/4", and carefully cut loose one end of the tube from its hydrolink fitting to install the insulating sleeve and then the camo cover, but it's worth it, I think. YMMV.
Disclaimer: no financial interest.