you can and i remember i did this ..oh about 1994 because i had an article from David Gentle.  It was in Muscle Mag and was called "Developing size and strength with Dumbbells" as i said this was from 1994.  David Gentle has a home page and you can email him ( he is in the UK ).  I can tell you one routine from this article...

you totally can (I know a lot of guys who train with powerblocks only)... it depends on your goals... can you be a competitive bber with dumbbells only?  probably not.  can you build a solid muscular physique?  absolutely. 

you totally can (I know a lot of guys who train with powerblocks only)... it depends on your goals... can you be a competitive bber with dumbbells only?  probably not.  can you build a solid muscular physique?  absolutely. 

For the last several years, I have used db's a lot more than barbells, and my progress has improved in both the strength and development departments. I'm not attributing my results to using db's in lieu of barbell work; I'm just suggesting that db work certainly has not hampered my progress. 

Can get an exceptional workout, and exceptional results, with using DB's only. 

Even using only a chinning bar (different grip placements) and dipping bar (suggest a "V" bar), with added weight when required, can give impressive mass. 

Far as quads/hams go, try Step-ups (as suggested by Montague) but have the bench/box/platform higher than usual.  This also hits the hams, because of the stretch required.  One legged squats are different from step-ups, with a more inline up & down motion, but still a very good leg movement.  When you get to the point of using a 100lb plus DB, you can understand the benefit of either/both these exercises.  Sissy squats can also be included.  Standing on one legs, a SLDL (DB) hits the hams very well.  Suggest it as a good movement for athletic training also.  Good Luck.