Another good timebuilding opportunity gone!
While 500 seems to be the magic number for most jobs, there are plenty of other jobs for guys under 500 hours! You just have to be willing to do a little research. I'm not sure what where you got your education and flight training and am not insinuating that this is you, but I went to a 141 school where everyone had the mentality that they would CFI at our school until they got picked up by a regional and never thought of anything else. Instructing is a great way to build time, I was a CFII and enjoyed my time as an instructor. But everyone was so closed minded about all of the other jobs out there that they never even looked at all the other possibilities out there.
There are quite a few banner towing places that will hired in the 300 range to the right person (beware of the shady places). There are a few aerial photography places out there that hire with basically a commercial. Traffic watch is also an option, I knew a guy who did that for a while. Great time builder, flew about 2 hours in the morning then instructed during the day and then went back and flew 2 more hours in the evening, Monday thru Friday. Like you said, flying divers could be another way to get your TT up. Plus most of the divers I hung out with were a blast!
I got info., made contacts (on here and FI) that led me to being offered 2-3 jobs. All that from just surfing the internet and doing some research on my own. These websites are a wealth of information and endless contacts. Take advantage of them and find something you want to do.
I know this sucks and is another blow for the low time time builders but you will find something. Heck you might actually like instructing, I know I did but I'm sure that would have wore off had I stayed there to long. Goodluck!