Personally I would not recommend a dalmatian as a second dog, they are how shall I say, attention hogs and are much like a pre-madonna... we had 1 that was a great dog (yes very hyper and very loud) but had to be carried down the stairs and wouldn't go out in the rain, he refused to play with any other dog for fear of (I assume) getting dirty... he made an excellent show dog though because of it but could not stand any other animals in his house with his family... he had a very high prey drive for the cats and hated any other dogs... and it wasn't just him, we had 1 a few years back that came into our rescue and was much the same way, also remember Dals are known for their deafness and also have a very high tendancy for seperation anxiety. This is just an opinion though!!!
My beagle makes an excellent companion here though (if you can get past the baying noises) and if he was a few years younger he would have even more fun. Another dog that we have had in rescu with a bully was a standard poodle, they are very fun loving dogs and seem to love everyone and everything they come across makes a great companion for both you and your bully and talk about a comedian.
These are just things that I have noticed through the past few years of rescue, we specialize in bully breeds but have the occasional few that come in otherwise.
Terriers can me menaces as well, especially JRT's... they are great dogs for your farm and such, but they have an instinct to herd and that they will do, whether it is your ankles or your bully's... and typically bully's will only take so much of that before they decide that they have had enough.
Look into maybe a sheltie as well, my ex has one and so does his brother and they love Bozkoe's brother... they tend to get along with almost anything as well too... maybe just watch any small animals that you have such as rabbits.
Hope that this helps a bit
Attached is a picture of Crestwoods just a lil hemi... he was 4 months old here and just starting his show career