I was thinking about this last night, as I know it's obviously a coding/organization problem to try to match up clients and freelancers who are on the same page about monetary expectations. Trying to categorize by project budget is troublesome, as there are often a lot of unknowns on the part of the job poster. The scope may be unknown, it may be part of ongoing work, etc.
What if instead of project budget, the job posters had to pick a 'Theoretical maximum hourly rate' for the work being done? Obviously this would only be theoretical, and the actual pay would depend on what is decided specifically later. But it would give a very insightful glimpse into the budget and hiring philosophy of a job poster.
For example, a job poster at a large corporation might put down a maximum hourly rate of $80/hour for a serious position, while someone in India looking for simple copy might put down a maximum hourly rate of $3/hour. They wouldn't have to end up paying these rates, but merely stating something like that would help match up clients and freelancers more efficiently.
I can't imagine any legitimate job posters who would feel uncomfortable giving a rough estimate of that number. I'm a freelancer who also owns my own business and who occasionally hires other freelancers. I would have no problem saying "The top hourly amount I'd be willing to pay for this website/HTML revision work is $80/hour" or whatever it is. This communicates the kind of quality I'm looking for and instantly would let freelancers know where I'm coming from and whether they wanted to submit an application. In my opinion, no legitimate job poster would have a problem with this.
There is no "theoretical maximum hourly rate".
The sooner and the better you want it, the more it will cost.
Wanting it "better", requires "more" expertise / experts: $ x man-hours.
Wanting it "sooner", requires more man-hours (which sometimes is not feasible / useful).
Any single person has the ability to draw on any number of additional resources that can add to their "standard" rate; at any given time.