Hi,
Regarding the long elevator lines and the large amount of guests without a room at the estrel:
What about providing some lockers for rent?
There are plenty of companies, providing mobile lockers within berlin area. Either as trucks (maybe parked near estrel, or on the estrel yard) or as moveable lockers-on-pallet (eg. to set up in the taxi-entrance below the lobby, the wide hall in the convention center, and in the fursuit lounge).
This would provide offsite guests with a place to store their bags, jackets, shopping goods, valuable suit parts, etc. (some even provide power sockets to safely load your mobile). And it would also greatly reduce the elevator use for onsite guests.
Maybe free of charge (on con budget), per use billing or rentable at onsite registration (or even in advance, to reduce the risk of additional costs for EF) .
Some examples:
http://carderobe.com/de/truck-mieten/http://www.eventlockers.de/sportveranstaltungen/http://www.japo.de/de/vermietung/schliessfaecher.htmlWhat do you think about that idea?