Sams and Sears both sell jacks that will work fine. People report the sams jack is lower so easier to get under the bike. I have the sears and have never had a problem but mine is at stock height and you do have to lean the bike upright to get the jack under it. I'm sure there are several others as well.
vilzrod, I'm not sure about the sams jsck but the sears jack has fairly thick rubber pads and really puts very little pressure on the oil pan. I have left mine on the jack for weeks at a time while I waited for parts to return.