The Cisco "deny" ACL seems to quietly drop TCP/IP packets. Is it possible for it to send either ICMP responses or TCP RST's in response to a denied request?
Short answer: no. Cisco IP Access Lists can only "permit" or "deny" (drop) packets.
Edit: I stand corrected. Configuring IP Unreachables on the interface results in an ICMP-unreachable message when the packet is dropped.
interface FastEthernet0/1 ip address 10.1.1.2 255.255.255.0 ip access-group 101 in ip unreachables end