I too have a 773T (previous naming convention for the S185) and find that I need more floatation and traction at times. My machine has the floatation tires (31.5”x13“x16.5”) so I may even have more traction that you, but is still not enough. I would love a track machine in addition to my tire equipped machine, but can't justify the cost of another machine. I do utilize my machine on asphalt, snow, and ice where a track loader may not be the best choice.
We have had a lot of snow this year and I expect a very wet spring. This means I will not be able to begin work until it dries up enough for my machine with tires to get around. I checked on the Loegering VTS system (which BobcatS250 mentioned), but it is not available for the wheelbase of our machines. I am currently looking at either McLaren Industries ProTrac systems (http://www.mclarenindustries.com/new/products.php?pID=3&PHPSESSID=e149ece287b75c280ff7f556e78d29d1) which are available in grouser bar, rubber pad, or magnum pad models. Contact McLaren industries for some information and they will send you an awesome DVD demonstating their tracks. Grouser Products (http://www.grouser.com/products/tracks/index.html) also offers their tracks in grouser, rubber, and steel pad models. I believe Grouser is the brand which Bobcat sells as their own cross bar tracks. I also believe Bobcat resells Loegering tracks as their loegering tracks. My dealer ordered a Bobcat part number for wheel spacers (to utilize chains on my loader) and the product which came in where Grouser brand spacers. BTW, Grouser will not sell direct, but can put you in contact with a dealer near you.
Overall, I believe you will get the additional traction and floatation that you require at a fraction of the cost compared to buying a T190. It is somewhere around a $16,000 - $20,000 price increase from a rubber tired skidsteer to a compact track loader. You should be able to get a set of over the tire tracks and wheel spaces for about $4,000. This will also give you the option of removing the tracks if tires are needed on asphalt.
Hope this helps.