I would go for the DT50 2x12 combo, or maybe just get a 4x12 cab, you can search the Line 6 DT 4x12 cab, it's not hard to find.
Also, you can search for a used Spider 4x12 cab, it's quite cheap and I think it has speakers that are similar to the ones in the DT cab.
Thanks for the response. Appreciate it.
I do already have the DT25 head and 1- 1x12 matching DT112 cab. I may try a 412 cab Spider.Don't know if it would be too loud. I did try a Mesa 412 once with a 25watt head and the sound was great. Nice and full. Not too loud with the head tammed a little. I do have a rock crusher attenuator so I could limit the level. I'll have to try it. I was thinking that two of those DT25 112 cabs might be a good mix. Just wondered if anyone did it. I heard good reviews with the open back combo and the extension cab together.