Yeah there are many types done with different methods, generally to concentrate the sugars within the grape, via climate (ice), fungus rot (Botrytis), timing (late harvest) or drying/sunning grapes like raisins.
Past recommendations here include:
Chateau De Fesles Bonnezeaux (Loire Valley, France) - Available at Carrefour
Isole Olena Vin Santo (Tuscany, Italy) - 1855 Bottle Shop (Somerset/Sixth Ave)
If you have the time you can drop by Culina where I think you can taste at the bar both icewine and Vin Santo to see which you like. They sell both at their deli shop.
I like Vin Santos, they are really excellent dessert wines. A common practice is to dunk a hard, brittle almond biscuit (cantucci) in it, as a nice, crunchy, nutty, sweet yet wet combination.
You can also try sweet German rieslings of residual sugar classification Auslese and above (Beerenauslese, trockenbeerenauslese) though these can be as pricey or even more than the Inniskillin.
I've tried this Austrian sweet wine as well: Tschida Zweigelt Strohwein, a straw wine of the Zweigelt grape, very nice. Available at Alfa Intl/ewineasia:
Hans Tschida Zweigelt Strohwein 2004 (37.5cl) - ewineasia.com