Just to add to my previous advice, as i have learnt a little more myself since that post... I would actually strongly recommend that if you are after a professional darbuka, it must come from a professional who has inspected (and preferably played) the instrument. The professional must be honest of course, but it is so important to obtaining a professional drum that you should never need to upgrade from. Buying any instrument online is so hazardous because quality can vary, and of course you are not able to try before you buy. Videos and sound samples cannot give the most accurate idea either, and for build quality you need to be able to hold it in your hands.
But like me, if you can't be there in person to pick your instrument, the next best thing is to have a professional or experienced player (who therefore knows what they're doing) pick for you. I've heard of some players offering this service in the past, and there is one guy in the UK here who seems to still do this. I think with enough digging and googling online, you may be able to turn up somebody offering such a service. Even the players at Arab Instruments here might be able to offer some in-depth insight into what they sell if you ask them...? Either way, it is a really good idea to have someone who knows what they're doing inspect and play the drum beforehand. If you know a trusted fellow drummer who plays darbuka and is able to play the drums in person, that might work - i have done this in the past for fellow musicians (for a wind instrument in this case, i have no in-person access to darbukas) where i have been able to try and buy straight from the maker on behalf of a friend abroad.
The other option would be 'Signature Series' instruments, though i would research each thoroughly first to learn all that be found concerning the production. A lot of instruments have their own series of models created by professional players. For example - Meinl have their Artisan Series and Toca have their Jamal Series darbukas. Initially, these may come across as higher end instruments, and indeed they might be in terms of construction and materials used. But usually the professional in question only has control and hands-on involvement with the initial prototype. Once the prototype is approved, the job is done, and the professional goes back to the busy lifestyle of being a full time musician. Yes the instruments are made to the professional's specifications, but they will be mass produced and will in most cases not be inspected by the professional who had them created. I realise professional musicians have lives of their own and can't be everywhere at once. But there's no avoiding the fact that, at the end of the day, all that has been created is yet another production line with just a name branded on them. There's no special treatment. I've read very mixed opinions on the Toca Jamal series, and not been able to turn up any opinions whatsoever on the Meinl Artisan Series...
The only exception to this that i've found are the Signature Series Tablas offered by Hossam Ramzy. In this very unique case, the production of each drum is overseen by Hossam. He inspects them and plays them (indeed, he pledges that every drum he sells is one he would play himself). This is, from my point of view, very very rare and a great opportunity to obtain something that will most definitely be a professional instrument.