SQL 2005: Can we determine how much the rebuild index maintenance job can grow database log files? On SQL server 2005, if all the databases are in Full mode (with hourly transaction log backups), is it possible to determine if rebuilding all indexes of a database can grow log file of a database? And how much can it grow?

If there is no straight answer then any directions would be really appreciated.

Thanks in advance.
Yes, you should look at the excellent whitepaper on this topic although it refers to the online index rebuild, it still has lot of good info 

http://technet.microsoft.com/en-us/library/cc966402.aspx

If the log files are auto growing then you can find that information using the default trace after the action is completed.

DECLARE @filename VARCHAR(255) 
SELECT @FileName = SUBSTRING(path, 0, LEN(path)-CHARINDEX('\', REVERSE(path))+1) + '\Log.trc'  
FROM sys.traces   
WHERE is_default = 1;  

--Check if the data and log files auto-growed. Look for tempdb, log files etc.
SELECT 
    gt.ServerName
    , gt.DatabaseName
    , gt.TextData
    , gt.StartTime
    , gt.Success
    , gt.HostName
    , gt.NTUserName
    , gt.NTDomainName
    , gt.ApplicationName
    , gt.LoginName
FROM [fn_trace_gettable](@filename, DEFAULT) gt 
JOIN sys.trace_events te ON gt.EventClass = te.trace_event_id 
WHERE EventClass in ( 92, 93 ) --'Data File Auto Grow', 'Log File Auto Grow'
ORDER BY StartTime; 
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