hardwood floor and speaker

Yes, lots of options...I went with Herbie's under my floorspikes, sounds fine, and they're cheap.
Some people also go to the rounded- nut type of stand spike, sorry, forgot what they're called.
You shouldn't have any problem coming up with something.

Replace the spikes with a carrage bolt, then add some felt pads to the bolt head. That is what I did with my vandersteen stands on a hardwood floor.

An area rug can help with any unwanted reflections.

Paul

Follow this link to what could work for you:

http://herbiesaudiolab.home.att.net/spkrfeet.htm#cone

Yes, carriage bolts, that's it.
Also, if you like one of the Herbie solutions, there is one that allows you to slide your speakers if need be. I bought the wafers that go under my brass pucks and they stick like glue to the floor once the stands/speakers are on them, they do not budge...if you go that route make sure you know where you want your speakers.

When I removed the carpet from my listening room a few years ago I used the carriage bolts with pads as P_Nelson suggests. Inexpensive and effective.