Geeks To Go, i applaud you for the way your contest was handled and appreciate the chance to enter.
you asked for suggestions for future contests, so here is my suggestion.
personally, i thought your rules were pretty straight forward and easy to understand so i would use the same criteria used for the Dragon contest, merely submit a printed logo picture (or screen shot). doing so would qualify you to enter into phase two of the contest.
the second phase would involve a printed logo pic in a public setting, the only caveat being that it has to be in a public place, not in a driveway or backyard,or dorm room. somewhere where it could actually be observed by the public. the contest judges have the final say as to if the entry satisfies their idea of "public" location. in my mind a cubicle in an office building is really not public. pass this phase go onto phase 3.
so you've demonstrated that you know the site (phase 1) and now are doing your part to spread the gospel (phase 2). phase 3 would require a demonstration of knowing your way around the site. it could be a hidden post, it could be a 300 word essay on the various threads that you find most compelling or even a particular post that helped you or could help others. this phase would not be judged, per se, but would be an additional step for contestants qualifying for this phase. the first 3 phases demonstrate a committment to not only win, but to the site itself. by now you have probably weeded out a number of entrants who are unwilling to think past the first day of a contest.
phase 4, present a "problem" to the remaining contestants, one that can be solved by using site content, but also allow for individual contestant input for a solution. using the site to solve the problem proves the value of the site to the contestant and those following the contest. the individual contestant input from this phase could be used as a tie breaker in the next phase.
phase 5 could involve creative effort, and you have to applaud anyone willing to put in the work to get this far. these people are serious about winning something and not just hoping for a lightning strike. the creative effort could be anything really, from good post or post reply, a photo or video, or a jingle. whatever, the purpose here is to allow the participant to take a stake in the outcome of the contest through creative effort.
phase 6, final selections and random drawing. the creatvity of an entry could be "scored" on an established scale, lets say 1-5 on any varitey of scoring elements (creativity, effort, impact, complexity, etc). this could give a little extra "weight" to a submission that clearly is superior to other submissions (say comparing a billboard ad to a classified ad). i would also suggest a "weighted" component taking into consideration the opinions of the site users. this would allow the contest to continue to generate "buzz" and hopefully drive traffic to the site as contestants enlist the aid of family and friends for high marks. any ties could be settled by the tie breaker in phase 4. the jugdes input would by the heaviest of the weighting to give them control of the contest they sponser (thats only fair). then of the remaining qualified entrants, do a random drawing, but some entrants may be assigned more than 1 random number for demonstrating excellence in any of the above phases.
i realize the HDX Dragon contest had a limited duration and a contest like the one suggested above might not have been practical for a short time frame. i like the multi-faceted approach because it does reward effort and desire to win above luck. that being said, its only an invited suggestion and is not an indictment of your last contest.
PS- if this turns out to be your best suggestion, do i win a T-Shirt? lol