Your description doesn't quite say what you mean by "pro quality" - that can mean many things. One possible solution would be actually using the supplied iMovie / iDVD software, pre-installed on your Mac (or $79 standalone if your machine is old). In iMovie you can generate transitions etc., export the thing as movie, and then burn it with iDVD.
iMovie will allow you to create a custom sound track, and you can also create 16:9 slide shows if that is what you desire (iMovie & iDVD 06). You have much more flexibility this way than with normal automatic slide show generators (such as iDVD alone), but it takes more time to create, too.
The problem with 99 images has nothing to do with DSP but rather with the DVD standard, which has a limit of 99 chapters per track. So your only way out is to create chapters that are longer than one frame - say a chapter mark every 10 images or so (thus for a max of 990 images).
If you use DSP then you can burn slide shows to HD-DVD, which has a much higher limit for chapters per track (I forgot exactly). Of course for that you'd need to get a HD-DVD burner and player, which is pretty pricy
DSP doesn't support Blu-Ray recording yet (does anything, anyway?)
The other option with DSP would be to create multiple tracks with 99 images each, and then link them together. In DSP you can link pretty much anything with anything, and make the DVD go from one track to another at its end instead of going to the main menu. However, you need DSP for this (iDVD won't do) and outside of costing a lot of money the usage of such power features is ... pretty tricky should we say.