Gaining Initial Telecan Uptakes

I am mulling the idea over of a directory site and I am trying not to leave any stones unturned in my initial due diligence.

So, some background. The directory will be construction related. I plan for it to be national entity with it spilt down into States/Counties and then into regions with this determined by population density. Obviously a quaint village with two residents simply don't work.

Within the niche, I have explored around 20 to 30 regions so far along with some States/Counties. I am coming up with search volumes between 250 - 650 exacts per region per month so I know the market exists. This is based on 3 or 4 kws per region.

Ranking the site per region I do not see as an issue. I already do this within a related field where I have around 100+ serps position 1, albeit this is an offline entity rather than a directory, but 3 - 4 kws per region is very manageable.

The idea is that each region will contain 10 contractors. The objective is to populate each region with a customer paying x per month for the listing. To ensure a fair crack of the whip for all, I will get the entries per page to rotate so each contractor gets equal exposure with a means of customer reviews built in to ensure the customer gets the best contractors.

So my dilemma, the bit that is a little grey for me at the moment is the initial site population.

I am toying with the idea of placing some initial free listings onto the regional page. I will place 5 listings free of charge and these listings will be the first five entries contained on page one serps to initially populate the page. These will be the contractors, that if initially called with a blank page, that will probably express the least amount of interest in the proposal on the basis that they will not see the perceived worth when they are already page one. These 'special' five are also the contractors that the other businesses in the niche will be aware of if they undertake any competition monitoring in serps.

The idea is to then telecan the additional entries in serps to fill the voids. Once we have five clients for the remaining spaces, two of the original free entries will be removed creating two further voids to fill. At this point I will go back to these, after removal, and ask them if they want to get involved. This is kept going until the spaces are filled and then we move onto the next region.

Trying to sell spaces when talking to a prospective client with a blank page is a non starter as nobody will want to be the guinea pig and this concept is the best way around this I have formulated so far. If I am honest it is leaving a bad after taste that I would like to avoid if I can see another path hence the reason for the post.

Does anyone have a better solution to this?