Get in touch with the Accessability Help Desk at microsoft. You will first want to download the drivers from the tobii website. After that the people at microsoft can help you get set up with Eye Control, They were very helpful with me. The glaring thing missing is an ability to scroll web pages.
The X8 is next to impossible to find used, but it is worth looking for. New, they are around $12,000 to $25,000, depending on the seating system and options. You can check them out at http://www.mobility-usa.com/extreme-x8--4x4.html. Note that they are made in Australia by Magic Mobility and distributed in the US by Innovation in Motion.
Another option is the Magic Mobility V6, which is a midwheel drive model with large tires. Chally has one of those and really likes it, as does Matt (Becky's (Nut's) husband).
Another option is a Segway or Ninebot conversion (Ninebot bought Segway). Blumil makes the X2. I have seen one in person and they are awesome, but more suited for a paraplegic. They require trunk and hand/arm movements to control and you must have arm and shoulder strength to lock the stabilizer when the power is turned off. You can check out the Blumil X2 at http://blumil.com/blumil-x2.php.
I have 4 wheelchairs. One was bought by private insurance (C500s VS). I have purchased 3 of them privately from craigslist. I have paid between $500 and $4,000 each for the used wheelchairs, typically spending another $1,000 each to get them sized properly for me.
Permobil makes snowtires for the drive wheels. They are great in snow, but also provide added traction on grass, dirt, and mud.
And, if you to take the next step, you could consider a four wheel drive wheelchair. Mine is the Magic Mobility X4 (about 15 years old). The current model is the X8 Extreme, which is better in every way. These come with 14 inch ATV pneumatic ATV tires, which are wonderful outdoors. While the wheelchair can be used indoors, it is not really all that practical to do so. It would be great for getting around the work site and storing in the toy hauler's garage. Be aware that they are a bear to back up in a straight line.
Those permobil wheelchairs are quite versatile and work well on sidewalks and trails. I have no problem using them in stores, etc. They are longer than some midwheel models and don't turn quite as tightly (but can still make a very tight turn). If you have tight corners in your house, that could be a problem.
I made a cardboard template of the wheelchair's footprint and used it to figure out what parts of the house I might have trouble with. If you are concerned, that is one approach to figuring out if you will need additional modifications to your house.
Larry, I am not surprised you are disappointed with the Quantum (was it a Q6 Edge?). I have spent a little time in a Q6 Edge and did not like it at all, for the same reasons you find it is not suitable. Heck, I could not even load the Q6 Edge into our van because I need to tilt the seat back to fit through the van door and that wheelchair would not move when tilted!
After trying many wheelchairs, I settled on a front wheel drive model. I could not find a way to make a mid wheel model work for my outdoor adventures (even on sidewalks and paved paths). I am a fan of Permobil. For smaller folks, the C300 is fine. For larger (not just weight, but also height), I recommend the C500. The newer versions are called the F3 and F5, respectively.