I would have to see pictures of your legs to comment about if one laser treatment would be helpful. I'm concerned that you were disappointed with laser results for your underarms and bikini. Is your laser technician experienced? what laser is being used?
Truly, electrolysis would provide you with what you want for BOTH your lower and upper legs because electrolysis treats hair in all stages of growth, it treats all colors of hairs on all colors of skin.
I have seen great laser results for lower legs, but very iffy results for upper legs / thigh area. A great percentage of thigh hairs have white bottoms (bulbs) and laser can't see white.
You will need several hours on the table for electrolysis, but the results are phenomenal. I would choose someone that does flash thermolysis (microflash, picoflash as offered on Apilus epilators), for example, so you can clear larger areas quickly.
Dee Fahey, R.N., C.T.
Licensed by the State Medical Board of Ohio for Nursing license and Cosmetic Therapy/Electrolysis license
British Institute & Association of Electrolysishttp://www.electrolysis.co.uk/?page_id=16