Hi James,
In theory, Pebble will allow you to customize the delimiters. It will look something like the following:
// construct the engine
PebbleEngine engine = new PebbleEngine();
// pull out the lexer and change the delimiters
Lexer lexer = engine.getLexer();
lexer.setPrintOpenDelimiter("<<");
lexer.setPrintCloseDelimiter(">>");
// compile the template
PebbleTemplate template = engine.getTemplate("templates/home.html");
// render the template
Writer writer = new StringWriter();
template.evaluate(writer);
However, I must admit that it is currently untested. I'm sure I tested it at least once during initial development but currently there isn't any unit test coverage for this feature. If you get a chance to try it out, let me know how it goes. Hopefully I'll get a chance to add some test coverage for this soon.