The 800 series is really a router with an optional integrated wireless feature.
Most likely, you are going to want to use a directional antenna for the optimal signal in most bridging environments. But, being that you are only going 50ft, you can certainly go with omni-directional antennas unless you have significant physical barriers that prevent LOS. The Cisco 1131, 1242 or 1310 would all function (1131 has internal antennae only, 1242 has external, 1310 has external but is also NEMA 4 rated if this is for an outdoor solution not being placed in an enclosure but only has an 802.11g radio where the 1131 and 1242 have an 802.11ag radio).
If there is significant 2.4ghz noise in the area, it may be beneficial to consider using 5Ghz (802.11a) for bridging as well.
Certainly, there are basic (less expensive) wireless bridging options from linksys as well. The Cisco solutions will offer higher MTBF, sturdier construction, and more configuration options.
I think what you want is the Linksys WET54G (Wireless Bridge). It acts as a wireless client, and supports WPA1 (but not WPA2). I'm not sure if it supports 802.1x or not, I think it's a RADIUS-like setup, but that's a whole other can of worms...
For a 50 foot installation, you should buy the Linksys model WET11, wireless-b ethernet bridge. You can buy them for about 30 bucks on ebay. Obviously you will need two so it will set you back about 60 bucks. Make sure the ones you buy come with a power supply. Needs 5vAC at 2 amps.
You get what you pay for, i would still do a total of 4x1242... Setup hot standby.
When referring to any sort of backbone connectivity, costs of downtime for 4 hours typically out weigh that of the initial investment.
Yes it costs a bit of money but the question comes down to how much your willing to loose during an outage.
The quality of a consumer product is simply different than that of enterprise. I think you would agree that a linksys freezing up or otherwise having 'issues' at my home is far more acceptable then impacting the business.