Having been down this road before ( http://www.advrider.com/forums/showthread.php?t=680675
), maybe I can offer some advice.
1) If you got the inseem for it, raising the suspension on the DL650 is HIGHLY recommended if you want to take the bike on anything more than graded fire roads.
2) If raising the suspension, I would strongly recommend limiting the suspension travel to around 7.5 to 8" max. You are raising the center of gravity and seat height, and I believe this is the point of diminishing returns on these bikes (i.e., clearance vs overall handing/performance/maneuverability).
3) If I was to design and manufacture a "raised" suspension kit to sell to the masses, it would include the following:
a) cartridge emulators- Ricor, Race Tech, Cogent...
b) longer damper rod
c) a longer decarbon-style (internal floating piston) shock, preferably with a body diameter capable of utilizing the OEM hydraulic preload adjuster. I would probably skip the external reservoir if I did it again.
I think that a vendor could put together a kit like this for about $1000 ($150 damper rods, $150 emulators, $600-700 shock) and still make a nice profit.
There's nothing wrong with using the stock fork tubes and just upgrading damping rods and adding emulators. The stock springs actually work really well in this setup too. Using the stock tubes really keeps the cost and complexity down, since you can use the OEM triples, gauge cluster, wheel, brakes, etc. The whole installation procedure is no more work than it would be to install the emulators.
I no longer own my DL650, since I got away from street bikes when my son was born (I'd rather spend my limited free time primarily in the dirt). A close friend of mine, who only lives 5 miles from me, bought it. He's put about 8-10k miles on it and absolutely loves it, and everything has held up great. If I was to get another Strom in the future, I would not hesitate to buy a suspension kit for it, as I described above.