I have seen oak carboy sticks. They are reuseable and go into the neck of the carboy. Let me see if i can find them.
Here we go:
OakBoy
A funny name, but a great alternative to conditioning and caring for a barrel. The OakBoy is a thin strip of air-dried, toasted oak that is designed for optimal extraction. Slender enough to easily fit through a carboy neck. Add an OakBoy into your wine; when the desired level of oak character is reached, transfer the OakBoy to another batch or rinse and dry it for storage. Use one OakBoy per five gallons of wine; leave in contact for a minimum of two to three months.
#9061 OakBOY American Medium
$4.50
EACH
#9062 OakBOY American Med Plus
$4.50
EACH
#9063 OakBOY French Medium
$4.95
EACH
#9064 OakBOY French Med Plus
$5.00
EACH
http://www.northernbrewer.com/pics/fullsize/oakboy.jpg