How well a PCI sound card works in DOS boils down to the chipset of the motherboard and the sound card you choose. Stay away from Intel chipsets other than BX/ZX/EX, the only exception are boards with PC/PCI (SBLINK) connector. VIA chipsets works well with ESS Solo-1 and Avance Logic ALS4000. SiS chipsets up to the SiS 962 southbridge seems to work fine with Yamaha YMF7xx PCI and Avance Logic ALS4000.
On the other hand you got PCI cards that relay on complicated TSR software like Sound Blaster (Ensoniq) PCI/Live!/Audigy and Aureal Vortex that also works on Intel chipsets up to the ICH5 at least. Also the YMF7xx PCI can gain better chipset compatibiliy by unsing a TSR called DSDMA but then you need to load EMM386 or similar and then you loose some game compatibility.
Maybe it's possible to modify one of Terratecs Solo-1 cards to fit inside a case intended for low profile cards as it's height is between low profile and full height. There's also a couple of low profile ALS4000 boards on Ebay any on my ALS4000 lot of the static noise could be avoided by muting the FM synth (it's actually a good OPL3 clone if you don't mind the noise).