Assuming you are talking about a SSB-CW transceiver, I don't recall ever seeing such a dual-band radio. There are a number of HF+6m transceivers to choose from. Yaesu, ICOM, Kenwood are the big 3. If you are in driving range of Universal Radio outside of Columbus, Ohio, you can see the new and used equipment up close. HTH.
For FM only there is a TYT TH-9800 that does 10m, 6m, 2m and 70cm for $279 at Amazon. Or the Yaesu FT-8900 for about $200 more. If you want SSB look for a used HF/6m all mode which can go for reasonable prices. I got a used Yaesu FT-857 for $400 and an Icom 706MKIIG for $400, both in good working condition, you just have to search around.
If you're looking for FM, my pick is a used Motorola Syntor X9000. These things have proven reliability and will do both 10 and 6 meter FM in a single package. Just know that if you do that, you'll still need 2 different antennas. Outside of the antennas, this is truly "set and forget." Leave it on scanning between 29.60 and 52.525 in the background and have your antennas on an A/B switch before you actually transmit.
For weak signal (SSB/CW) work, I have an Icom transceiver that will do 10 meters and I use a Downeast Microwave (DEMI) transverter with it for 6 meters.
The Radio Shack HTX 100 was a good inexpensive SSB rig for 10M. You can find them used for around $100 and up. The Ranger 5054 was also a nice 6M rig, and you can find them used for a little bit more than that.
I recommend the Yaesu FT-8900R if all you want to do is FM; they are a bulletproof and proven radio that just keeps going and going... (where's the Energizer Bunny smiley?). If you have sufficient space and a place to properly mount a HF antenna, then a "multi-mode" radio like the IC-706 series or IC-7000/7100 will do a great job. Many hams also find the Yaesu FT-857D to perform and hold up very well.