Line Number Bookmarks for Quick A–B jumping

I dearly miss a bookmark feature for simple A-B(-C,-D,-E, ...)-testing/-jumping. (Something along the lines of TextMate's ditto.)

I.e. where you can add little star'ish symbols next to row numbers and then be able to hit, say, F2 to jump between the bookmarks (in which said bookmarks would be saved along with any other page-specific edit state meta).

If it was up to me, I'd prioritize navigability (bookmarks) over clarity (code folding) in Coda's development. Yes, as per current specs, one can add things like /* !bookmark */ in the code, for said bookmark functionality, but I'd rather prefer not to:

The bookmark functionality I'm hoping for shouldn't be dependent on actual code editing in order to take place. I think the current Code Navigator is great, but for starters, the practice of making these !bookmark comments in the code isn't fast or transparent enough... My perception of the Code Navigator is that it's more of a selector/navigator for fragments of your code; not necessarily a down and dirty A-B-jumper between two or three places on each document. (Which, of course, may be fodder for further arguing; that this is what the Split view is meant for, but, well...) (...hehe, I realize that I'm taking a pretty defensive stance here, without any prior, opposing arguments (sorry), since this is one of those dear features I've left behind, from TextMate...)