Almost didnt bother to respond to this because this site has gotten so miserably slow (both in page loading/ and activity).
Anyway, in response to your dilema. IMO, the "best" way (for any XJ rocker panel repair) is to get some 2x3 1/8"wall boxed steel tubing, the length of each rocker, cut the rockers out from front wheel opening to rear so that the top edge of your tube rides flush along the bottom edge of door opening and set back "into" (so-to-speak) the old rocker area so that it isnt sticking way out, and welding into place all the way around and of course using weld thru primer and treating and painting the area afterwards to prevent further degradation. Also cap the ends of the tubes of course to keep moisture, mud, etc. out of the tube. (Added bonus is you can install bungs and fittings that would allow you to use them as air tanks, thus have an emergency tire filling source with you where ever you went) This will give you a cool "rock rail" that will effectively strengthen the chasis (greatly increases side impact protection for the passengers, and believe me it is needed in an XJ, I personaly have seen several after side impacts). Check out this one, granted this was after a semi hit it, but I have seen others with a simialar type of damage after being hit by a car.
http://tellico.off-road.com/wwwthrea...1217765-03.jpg http://bbs.off-road.com/wwwthreads_u...1217763-02.jpg
If you can do the work yourself, I would say you should be able to pull it off for well under $300, if you go to a shop that is capable, probably in the nieghborhood of anywhere from $500-$1,000 give or take.
You could probably get a shop to do a hand formed patch panel repair for a lessor price, but you wouldn't get all the pluses you get doing it the way I have described. Just my thoughts on the matter.