I've made a high res here for the Dutch market but it does include a lot of international channels as well as they're available to the market;
http://forum.kodi.tv/showthread.php?tid=228519
I disagree with the current ratio's being mentioned, strongly.
BTW I do have most of these as either .EPS or .SVG so I can make them any resolution or any size I want.
For now I"ve decided on 800x450 which is 16:9.
Why this? For starters not all logo's are square or do fit in a square easily, some are quite long and if this was the case I searched for one which did fit the ratio better.
You see when these get scaled down they become unreadable, let's say if the were 150x800 which happened a lot.
In these cases I've searched for a split version of the logo or a small alternative one.
The ratio of 16:9 did work the best for logo's for me as you can see from the above, I've exiremented a lot with this since the begin days of MediaPortal (about 2001/2002'ish) all the way up to now. Then there's the design... it's really a jungle out there style wise.... I pretty much went with the flat design where available if not all I believe. For this way I suggest a pack rather than a database to make them fit in with each other and the skin. i would support a database but only for let's say I could maintain the logo pack myself for my provider, just as loose logo's I don't see it working out.
Edit: Oh i forgot 1 thing, there's also design; they keep bloody changing them and some channels lost each season!
The pack I made has all the current ones out there.
![Full sized picture Image](http://i.imgur.com/MWqITSm.png)
Pic from my backend for planning recordings etc... Here you can see nicely that square doesn't really fit best and rectangular is better. I agree some logo's could use a bit more space on the bottom or on top but it scales far better overall for all logo's this way.