perhaps i can offer something to assist in your approach more than direct input on your query.

i beleive it helps to realize that "best" is a fiction. what one has to do is realize everything is a tradeoff. identify the specific items where you want to bring improvements and optimize in those areas, realizing you may very well end up sacrificing in other areas.

the fundamental trade-off in computer science is memory and speed. one can make an process execute faster by using more data structures, or one can conserve memory by doing more computation. [these constraints may be altered once quantum computers are generally available, but until then...]

in the wireless/portable component market, one has to deal with weight, size, power, heat, etc. in the server arena, one will have to deal with bandwidth, through-put, capacity, etc.

the up-shot is first have clearly defined objectives for your app server. what improvements or innovations do you want to develop? then identify the parameters. once you have a clear defintion of where you are going, the other areas become easier to focus on.

enjoy!