Have racked my brains about this for months, and spent a couple of days
messing with every option I can think of,
and while I now understand better the problem
I cannot fix it.

THE PROBLEM - SIMPLIFIED
I like a noisy boot, with lots of messages
that tell me what is happening, what is causing delays,
what has failed (in case of non-boot) etc,
not to mention impressing the pants off Windows admins.

Up to Kubuntu 10.10 I could easily get this just by
removing the "splash quiet" options from the grub kernel line.

But with Kubuntu 11.04, even after I remove "splash quiet",
then during boot, after the grub screen
I get a 15" (Fifteen second!!!) black screen,
then finally a few text lines, then the login prompt.

THE PROBLEM - DETAIL
Up to 10.10, the boot console would display kernel messages
(as shown after boot by dmesg)
and boot log messages (as in /var/log/boot.log)
mixed together.

From 11.04, the boot console only shows boot log messages,
the kernel messages are missing,
which leads to a mostly black screen booting process.

In fact I can see that the kernel messages seem to be going to tty1
(can see them there when I temp switch to tty1 at the gui login prompt).
So I could probably fix this problem if I could get these kernel
messages back to tty7,
which I think is where boot happens?

But editing /etc/default/grub to:
GRUB_CMDLINE_LINUX="vga=795 console=tty7 loglevel=7"
does not return the kernel messages to the boot console where I can see them.

I realize my love of a noisy, turbulent boot process is against the march of progress
but if anyone knows how to get back my lovely, informative, educational, verbose boot process, I would be grateful