How about this: add one player to make it 8. Divide players in two groups of 4. They play 3 rounds. First two in each round form a group of winners.(and 3rd and 4th could also form a group). Results of the games between players that qualified frim one group count in the final, so they play only against the players that qualified from the other group. That gives you 3 rounds in qualifiers and two round in the final, total of five rounds.
tournament mode for 7 players

Good idea but we are only 7(!) players and I it is not possible to change this number of players(no more available).
May be we can use this round-system for 7 players too. We have a group with 4 players and one with 3 players. And from each group 2 players qualify for the final two rounds. Or would this be too unfair?
It is an internal tournament of our club so a bit luck is acceptable. ;-)

The 30 second bonus sounds like WAY TOO MUCH but since I play relatively little live chess maybe some more opinions are needed here.

No, 30 seconds bonus per move is quite common now. See e.g. a great chess tournament series in Czech Republic.
http://www.czechtour.net/olomouc-chess-summer/regulations/
I like it because you can not lose on time.
Round robin with 7 players is 6 games, just give each player 1 bye.
That is already built into the pairing tables--they would use the RR schedule for eight players and all games against 8 would be a bye.
http://home.comcast.net/~wporter211/realsite/chess_etc/rrpair.htm
Hi,
I search an idea to play a reasonable tournament with long time to think (e.g. 1:30 + 30sec bonus) for seven players. Round-robin needs 7 rounds which is a bit long.
We would prefer 5 or 6 rounds. But swiss system is not practicable.
May be something with a preliminary round...
But I need a real advice. I'm not so familiar with organizing tournaments.
Thanks in advance
Thomas