Markdown + Latex for iOS
Solution 1:
The short answer is "no", I've been looking myself.
TexWriter is a decent LaTex editor and preview but I don't know of a MarkDown one with inline LaTex.
Further, you might want to check out Brett Terpstra's page devoted to iOS editors for a great list of editors and keep an eye out for any that add "LaTex" as an extra feature.
Solution 2:
Dropbox paper works on iPads. Typing in $$ will start an inline latex environment.