Gents,
I have a 1903a3 rifle that I'm looking for a new stock and handguard to replace the original stock. It's a shooter with little collector value and I'm looking for businesses that sell 1903a3 stocks/handguards.

theres a ton on google

this will get you started, http://www.gunpartscorp.com/Manufacturers/USMilitary-33541/Rifles-42386/SpringfieldModels-40111/Springfield1903A3-42095/StocksHandguards-42072.htm

Depends on what you are looking for specifically.  Are you looking for an original stock or an aftermarket?  Looking for a straight S stock or pistol grip C stock or are you ok with a scant stock.  The Minelli stock from Brownells is a very nice c stock that needs minimal fitting.  The CMP sells a 1903 C stock that will need a little work but are good stocks.  Numrich has NOS scant stocks that will need a little fitting and shaping.  eBay and gunbroker always have original stocks going through auctions.  Sarco sells original s stock that are relatively cheap but don't expect a beautiful stock with crisp cartouches.

I have never bought a Minelli stock but have seen several and they are very nice stocks.  One other option is to call Dupage trading and see what they have instock.

I'm looking for the type 11 stock seen in the link below which is a straight grip style.

http://www.trfindley.com/origstmps/m1903guideb.jpg

this one? http://www.gunpartscorp.com/ad/585400.htm

The majority of 1903A3 S stock that are being sold by Numrich and Sarco are going to be the Type 10 in that chart, having cross pins instead of cross bolts.  Your best bet for a "Type 11" stock with cross bolts is either eBay or the CMP forum.
The C stock is more comfortable to shoot, especially in prone, and looks good.  
Also don't discount the scant stock.  Some have some very nice wood and are also comfortable to shoot.  

Thanks for all the help gents. I appreciate the input and I will look into figuring out a good stock to purchase from these vendors. I didn't take into account a prone shooting position but that definitely is something I'll keep in mind.