Just wondering if there is a limit to how much a potion can boost your skill, such as the blacksmith potions that do +#% Blacksmithing or similar for enchanting?

Such as say, Enchant some gear for +Alchemy > Make a potion for +Enchanting > Enchant gear with +Alchemy . . . . and repeat over and over. . .

Just wondering if this would allow me to (with patience) make a oh. . . Boots with +100000 Stamina.

You can only loop it around something like 2-3 times before the algorithms reach their peak.

You can use JUST alchemy though with restoration potions. Get fortify enchanting 30000% things like that.

Can you? I didn't know that. What's the process to do this?

Without Fortify Restoration potions (that's a whole other issue) the caps are:

Fortify Alchemy/Smithing Enchantments: 29%
Fortify Enchanting Potion: 32%
Fortify Smithing Potion: 130%

Assuming maxed skills and relevant perks you need to:
1) make enchant potions
2) make alch gear with potions
3) make enchant potions with gear
4) make new alch gear with new potions (29% cap reached here, can safely make smithing stuff)
5) make new potions (32% cap reached, these potions over step 3 potions only effect a few enchants)

http://www.uesp.net/wiki/Skyrim_talk:Alchemy#Breaking_the_Game_with_Alchemy_.28and_maybe_a_bit_of_Enchanting.29

Evil. Positively evil.

Its like Bethesda forgot to balance crafting like they balanced the rest of the skills.

Also loot in game needs to be balanced too. No high level crafting ingredients should be obtainable at low levels from merchants.