This style for Google Calendar hides the #topBar area (white space) and moves the notification messages and search box/buttons (and logo) to still visible locations (except for the logo if you're hiding the nav bar on the left :D). NOTE: you need to have an inner window size (content area of the browser) with a width of [about] at least 1324px** (meaning, a wide-screen monitor essentially) or it won't work very "cleanly". (If you don't have a window that's wide enough, then you can still use another style which hides the #topBar--I've got three other such styles myself.)

* * * * NOTE * * * *
The user in question has switched to http://freestyler.ws/style/42607/gcal-hide-search-box-till-hover-show-google-nav, so I won't be maintaining this one. If/when this style breaks due to changes by Google, then I'll just delete it.
* * * * * * * * * *
(created by request - and, yes, I know what it looks like on the Event details page when the content window isn't wide enough--as I said, "wide-screen", but it displays as requested (acceptable overlay). :D If you don't want the search box/button/link there at all, then add a z-index with a value of 20 [or greater] to either (a) div#ep-header (pre-26Aug2010 version) or (b) div.ep-ea (new version as of 26Aug2010--if your account has been updated) [and you'll need a not-quite-as-wide wide-screen].)

**On most days you can get by with 1204px--unless your viewing range crosses the end-of-month, when you might need 1237px; when your viewing range crosses the end-of-year, you could need up 1274px. There's a small "fudge factor" for spacing (but only a few pixels worth--and none of them are on the Event details page where you need 1324px all the time [unless you remove the search box from that page altogether using a z-index value]). The range format takes one of the following:
(1) Mmm dd - dd yyyy
(2) Mmm dd - Mmm dd, yyyy
(3) Mmm dd, yyyy - Mmm dd, yyyy

I haven't tested it in Google Chrome yet.

Updates...
29May2011: fix a syntax error (z-index for #nt2 message**); adjust position for new Google nav bar
27Aug2010: update for the new [create, view] event details layout

(** too weird--since the syntax error would have made it NEVER work, I have no idea how it could have gotten there in the first place)

The image below shows 3 screenshots: #1 (top) - typical Calendar #topBar area (this style disabled); #2 (middle) - this style enabled; and #3 (bottom) - this style enabled and 'Show search options' selected. Plus, here are two more images--one with the nav bar on the left hidden and one with it displayed (by :hover)--showing this style enabled (and with the logo visible):

http://img822.imageshack.us/img822/7518/gcalmultiweekgridaio12j.png
http://img708.imageshack.us/img708/2585/gcalmultidayweekgrid2ai.png